In general, a blind spot detection system is a system intended to increase convenience of a driver by giving the driver a warning when an obstacle is found in the dead angle area of a rear side of a vehicle during driving, or when there is the risk of colliding with an obstruct in a blind zone upon the lane change of a vehicle or the risk of collision resulting from a lane change of another vehicle that approaches the vehicle at high speed from a rear side of left and right seats.
As illustrated in FIG. 1, the blind spot detection system has a sensor 2 installed at a rear side of a vehicle 1, wherein the sensor 2 detects a blind spot detection (BSD) zone, a lane change assist (LCA) zone, and a rear pre-crash (RPC) zone, and notifies drivers of approaching vehicles from these zones using a warning light.
As the structure of a rear cross-traffic warning light transmitting a warning signal from the sensor 2, the structure illustrated in FIG. 2 has been commercialized.
Referring to FIG. 2, when a detection signal is transmitted from the sensor via a wire 40, a warning signal is transmitted to a light source 30 formed in an inner portion of a reflective instrument 10 via a connector 50.
In this case, the structure is implemented such that, when light is emitted from the light source, the light reflected on a surface of the reflective instrument 10 penetrates an optical sheet 20 so that the warning signal can be transmitted to the outside by projection of a part of the light.
However, the structure as illustrated in FIG. 2 is mainly installed inside a side mirror of a vehicle, or a reflective mirror in an inner portion of the vehicle, and in this case, a space for receiving the reflective instrument 10 capable of securing reflection is needed. Thus, there are many limitations in forming a thickness of the entire instrument because such a space should be secured.
Moreover, when optical patterns are formed in an area where the light penetrates the optical sheet 20, merely reflection light is transmitted. Thus, since uniformity of the light cannot be secured, it is problematic in that uniform light may not be appropriately provided to the optical patterns.
In particular, it is problematic in that light efficiency is remarkably reduced because merely reflection light is implemented due to a very large inner space of the reflective instrument 20.